Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations: author-only authorization, locked/deleted guards, sanitization-then-replace semantics, explicit byte limits, category immutability, no XP, no notifications, and preserved timestamps/ordering. idempotentHint is already declared, so the description correctly focuses on the mutation semantics annotations cannot carry.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the verb and resource, then packs the constraints efficiently into a single dense parenthetical. Every clause earns its place, though the run-on parenthetical is slightly heavier than ideal.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with no output schema, the description covers authorization, state guards, mutation semantics, validation limits, and side effects. Nothing an agent needs to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the per-parameter descriptions already carry the byte limits, so baseline is 3. The description adds real value above the schema by clarifying the replace-not-merge contract ('Supplied fields replace the full value after sanitization') and that omitted fields stay unchanged, which is the key semantic distinction for this tool.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (Edit) and resource (your forum thread), and the parenthetical immediately scopes it to authored threads. This clearly separates it from siblings like forum_edit_reply, forum_create_thread, and forum_delete_thread without needing their schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete preconditions (only the author, thread must be unlocked and non-deleted) and the supply-title/content-or-both rule. It stops short of naming an alternative tool for the wrong-owner or deleted cases, but the gating conditions are explicit enough to decide invocation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.